1. FIELD OF INVENTION
This invention relates to fluid handling apparatus or machines, such as pumps and the like, driven by a motor and a shaft means. A multi-stage mechanical seal assembly is located between the fluid handling apparatus or machine and the motor to progressively reduce the pressure of fluid leakage along the shaft and substantially prevent the leakage of product fluid to the motor. The invention is particulary concerned with the driving connection for the shaft sleeve between the fluid machine and the motor.
2. BACKGROUND DISCUSSION
Multi-stage mechanical seal assemblies are widely used with nuclear reactor coolant pumps, boiler recirculating pumps, boiler feed pumps and pipeline pumps (to name a few of the uses), and will meet the requirements for extreme and widely changing pressures and temperatures encountered in these uses. It is to be understood that the present invention can also be used in less demanding installations. Additional discussion of operating conditions is found in Marsi et al Pat. No. 4,586,719, issued May 6, 1986, which is incorporated herein by reference.
The multi-stage mechanical seal assembly, as described in the aforesaid Marsi et al patent comprises a plurality of seal stages, each comprising a rotatable seal ring and a non-rotatable seal ring, each seal ring having a radial seal face with the faces of the rotating and non-rotating seal rings of each seal stage opposing one another. The multi-stage mechanical seal assembly of the aforesaid patent is constructed as a cartridge and is assembled onto a seal sleeve received on the shaft of the fluid machine. The seal sleeve is connected to the shaft to rotate therewith. The fluid machine shaft and the seal sleeve are generally drivingly connected to the motor by means of a cylindrical coupling.
In previous constructions, a single key was used for torsionally coupling a one-piece connective sleeve. One or two pins at the lower end of the connective sleeve locked the lower sleeve to the upper connective sleeve. This type of connective means has been found to be unsuitable for the inventive seal arrangements being described herein.